Diabetes knowledge among Malaysian adults: A scoping review and meta-analysis

Abstract Introduction: Optimal self-care promotes glycaemic control and prevents diabetes complications. Its performance is facilitated by an adequate level of diabetes knowledge. This review aimed to evaluate diabetes knowledge among Malaysians by assessing diabetes knowledge scores and their associated factors. Methods: A comprehensive bibliographic search for Malaysian studies on diabetes knowledge was conducted in PubMed, Scopus and Google Scholar. Relevant literature was systematically selected and described; pertinent data were extracted; and data on diabetes knowledge levels and their associated factors were synthesised. The quality of the identified studies was assessed using a Joanna Briggs Institute critical appraisal tool. Results: Thirty Malaysian cross-sectional studies that measured diabetes knowledge levels were retrieved. Nineteen of them used a named diabetes knowledge measurement tool, with 14 using the 14-item Michigan Diabetes Knowledge Test. A low knowledge level was prevalent among patients with diabetes mellitus (pooled mean knowledge score=6.92, proportion of patients with a low knowledge level=47.97%). The knowledge score was associated with some sociodemographic variables, health literacy, self-care and glycaemic control. Conclusion: The association of diabetes knowledge with diabetes outcomes (e.g. self-care and glycaemic control) reflects the potential of the former as a target of intervention. Periodic measurement of diabetes knowledge in healthcare settings and among populations can help in assessing the effectiveness of diabetes educational interventions. Concerted efforts to improve diabetes knowledge among Malaysians have the potential to fill knowledge–practice gaps.


Introduction
Diabetes mellitus is a major chronic disease that yields increasing burden in low-to-middleincome countries. 1In the National Health and Morbidity Survey in 2019, 3.9 million (18.3%) Malaysians aged 18 years and above were found to have diabetes mellitus, 2 a considerable increase from 13.4% reported in the national survey in 2015. 3 National Diabetes Registry (NDR) 4 recorded 1,614,363 patients with diabetes mellitus from 2013 to 2019, of whom 99.3% were diagnosed with type 2 diabetes mellitus (T2DM).In 2019, the NDR audited 181,634 patients with T2DM from 830 public primary care clinics.A considerable prevalence of comorbidities was reported for these patients: 80.4% for hypertension, 74.3% for dyslipidaemia, 14.6% for nephropathy, 10.6% for retinopathy and 5.9% for ischaemic heart disease.Further, glycaemic targets (>6.5%) were not achieved in 67.6% of these patients.4 Diabetes mellitus requires appropriate and persistent self-management, including healthy eating, physical activity, blood glucose monitoring, medication adherence, good problem-solving skills and healthy coping skills.5 Better selfcare practice is likely to lead to improved glycaemic control among a ected patients, as shown in the systematic review by Chrvala et al. 6 It has been found that 95% of diabetes care can be achieved by patients with diabetes mellitus themselves.7 Although appropriate usage of antidiabetic medications is vital, e ective diabetes management also depends on patients' knowledge about the disease and practice of self-care activities.8 Research has shown that more knowledge is associated with a predisposition to assume self-care, leading to reduced stress associated with the disease, higher receptivity to treatment, better trust towards medical professionals, higher selfesteem and self-e cacy and a more positive selfperception of one's health.9,10 Diabetes knowledge can be measured using various measurement tools.Recognition of REVIEW REVIEW baseline diabetes knowledge is important in educating patients with T2DM to help them manage their disease e ectively.In other words, assessment of the knowledge level contributes to the design of personalised educational interventions tailored to the individual needs of patients with T2DM.Hence, determination of patients' knowledge levels and identi cation of speci c knowledge-practice gaps should be rst conducted for the implementation of e ective and individualised diabetes education.11 In a systematic review performed among patients with T2DM in Southeast Asian countries, data on diabetes knowledge were available from only three out of eleven countries.12 Out of the seven studies included in this study, only four studies were conducted in Malaysia.However, there were some methodological concerns in this review, as synthesis was conducted although the respondents were variable (patients versus non-patients) and di erent diabetes knowledge scales were used.12 To date, no national study has yet evaluated health knowledge among patients with diabetes mellitus and the general population.ere are a substantial number of Malaysian publications on diabetes knowledge; these publications show that the prevalence of low knowledge levels could range from 33.6% a11 to 73.5% a3 even though the same knowledge questionnaire is used.us, a comprehensive review of Malaysian scienti c literature is warranted.
is review is anticipated to provide data on the types of knowledge assessment tools used and the factors a ecting the knowledge levels.
e ndings could help in the identi cation of new targets for interventions for better management of patients with and without T2DM in Malaysia.An understanding of the level of diabetes knowledge is also helpful for health educators to plan for future diabetes programmes.

Methods
An extensive literature search using a combination of the search terms 'diabetes mellitus', 'knowledge' and 'Malaysia' was conducted in electronic bibliographic databases including PubMed and Scopus supplemented by Google Scholar.e criteria for inclusion of studies to this analysis were as follows: (1) study setting: communities, primary care clinics or hospitals in Malaysia; (2) study participants: adults (≥18 years of age) with diabetes mellitus as well as healthy adults; (3) measurement: general health knowledge about diabetes mellitus; and (4) study design: cross-sectional.
Only original articles were included in the list for analysis.Books, monographs, reports, case reports, conference abstracts, editorials, letters, comments, reviews (narrative or systematic), study protocols and theses or dissertations were excluded from this scoping review.ere was no limit set for the year of publication.
e literature search was performed from inception to 17 January 2022.e retrieved references were managed using the EndNote X20 citation manager (London: Clarivate Analytics; 2020).e keywords of all citations were coded for the study designs, study settings (ambulatory care or tertiary care) and diabetes knowledge and its associated factors.
After studies to be included in the analysis were nalised, the full texts of all eligible studies were retrieved.A pair of investigators independently screened the titles and abstracts of eligible studies and reviewed the full texts for methodological validity.When multiple publications of the same study were retrieved, only the most recent relevant data were extracted from these publications.
is scoping review was prepared following the PRISMA-ScR checklist. 13 quality of the identi ed studies was assessed using the Joanna Briggs Institute (JBI) Checklist for Prevalence Studies, since it is speci cally designed for prevalence studies and has high methodologic rigour.14,15 As there is no generally acceptable threshold for an 'acceptable' JBI score, studies with a score of 5 or less (suggesting high likelihood of a poor study quality) were excluded.Subsequently, two investigators extracted and entered the following data independently into a data extraction form: (1)

Search results
e online database search yielded 479 results from PubMed (n=156), Scopus (n=160) and Google Scholar (n=163).After 196 duplicates were removed from the list, 283 potential studies were further ltered by reviewing their titles and abstracts.An initial list of 40 publications was considered for analysis after excluding irrelevant studies such as studies not conducted in Malaysia, randomised controlled trials, letters, studies not related to diabetes knowledge, qualitative studies, conference abstracts, study protocols, reviews, non-journal references and interventional studies on the e ectiveness of an intervention or a programme (Figure 1).After the full texts were examined, eight publications were further excluded owing to a low JBI score.

REVIEW
Studies included irty studies published from 2006 to 2021 were included, all of which were crosssectional studies.Kindly see appendix for the full list of articles.

Study participants
e majority (n=24, 80%) of the studies involved patients with T2DM, while seven studies (23.3%) involved healthy individuals.Two studies recruited both patients with T2DM and healthy individuals, a12,a30 while one study involved both patients with types 1 and 2 diabetes mellitus.a28

Study settings
Twenty-one studies (70%) were conducted in ambulatory care facilities (i.e.public primary care clinics, hospital outpatient clinics or pharmacies), while 10 (33.3%) were conducted in community settings.One study was conducted in hospital and community settings.a30 Fifteen studies were performed in primary care settings, a2-3,a6,a8,a12-14,a17-18,a20-22,a25,a27,a29 and four of them were also conducted in hospital settings.a13,a17,a25,a30 Study objectives e objectives of this scoping review included the following: (1) validation of diabetes knowledge measurement tools, (2) evaluation of diabetes knowledge measurement tools, (3) assessment of the prevalence of low knowledge levels among patients with diabetes mellitus, (4) comparison of diabetes knowledge between Eleven studies used adapted/modi ed or self-developed questionnaires to measure diabetes knowledge (Table 2).ere were marked variations in the contents covered, with the number of items varying from 11 to 68 scored using di erent methods.Only three studies reported psychometric data prior to data collection. 23,28,44

Diabetes knowledge level among patients with diabetes mellitus
Of the 15 studies that used the MDKT, all except one a1 used the MDKT-14.Of these 14 studies using the MDKT-14, 11 reported the diabetes knowledge level using means or proportions.Two studies did not report the above-summarised data, a9,a29 and one study used a di erent threshold for the low knowledge level (score <11).a15 e 14 studies had JBI scores ranging from 6 to 9.
In view of the similarity of the measurement tool used (MDKT-14), the extracted data were synthesised.As shown in Figure 2, seven studies involving 2483 participants reported mean MDKT-14 scores ranging from 6.10 to 7.77 with SDs ranging from 1.22 to 3.08.A metaanalysis of these data ( xed-e ect model) revealed a pooled mean score of 6.92 (95% con dence interval [CI]=5.45-8.39).When the study by Tam et al. a27 (healthy adults) was excluded to limit the meta-analysis to only patients with diabetes mellitus, the pooled mean knowledge score was 7.02 (95% CI=5.45-8.60).As shown in Figure 3, seven studies involving 2024 participants reported the numbers or proportions of participants having a low knowledge level.A meta-analysis of these data (randome ect model) revealed a pooled proportion of a low knowledge level of 47.97% (95% CI=39.13-56.88).When the study by Hasbullah et al.a16 (healthy adults) was excluded to limit the metaanalysis to only patients with diabetes mellitus, the pooled proportion was 48.10% (95% CI=37.61-58.68).

Diabetes knowledge between individuals with and without diabetes mellitus
Two studies assessed diabetes knowledge among individuals without diabetes mellitus using the MDKT-14: Tam et al. a27 reported a mean (SD) knowledge score of 6.20 (2.15), while Hasbullah et al.a16 reported a proportion of a low knowledge level of 47.22% (95% CI=41.34-53.17)(Figures 2 and 3).Conversely, two studies compared diabetes knowledge between individuals with and without diabetes mellitus using the same scale simultaneously.a12,a30 Ding et al. a12 found that the overall knowledge score was signi cantly higher among patients with diabetes mellitus (81.8, SD=10.9)than among patients without diabetes mellitus (64.0,SD=20.9).Yun et al. a30 showed that the mean total knowledge score was signi cantly higher among patients with diabetes mellitus (24.4,SD=3.83) than among healthy individuals (20.2, SD=5.97).

Factors associated with the diabetes knowledge level
ere was considerable heterogeneity among the included studies, particularly in relation to the diabetes knowledge measurement tools used.In many studies, diabetes knowledge was not the main outcome measure.
In terms of sociodemographic data, Al-Qazaz et al. a7 reported that a lower educational level and an older age, but not sex and ethnicity, were associated with a lower knowledge score (P<0.05)among patients with diabetes mellitus.Chua et al. a11 showed that an Indian ethnicity, a lower household income and a lower educational level were signi cantly associated with a lower knowledge score (P=0.003,P=0.027 and P<0.001, respectively).Lee et al. a20 demonstrated that an Indian ethnicity and a lower educational level were signi cantly associated with a lower knowledge score (P=0.005 and P<0.001, respectively).
In terms of health literacy, Abdullah et al. a2 used the HLS-EU-Q47 to measure this variable.
ey found that patients with adequate health literacy had a higher MDKT-14 score (P=0.019).
In terms of glycaemic control, Abdullah et al. a3 failed to observe an association between the HbA1c level and MDKT-14 score.In contrast, Al-Qazaz et al. a7 found a signi cant linear correlation between the HbA1c level and total knowledge score (r=−0.39,P<0.001).
In terms of self-care, Ishak et al. a17 used the Malay Elderly Diabetes Self-Care Questionnaire.
e authors reported that better diabetes knowledge was associated with self-care (P<0.001).Yap et al. a29 found a linear correlation between self-care based on the Summary of Diabetes Self-Care Activities questionnaire score and diabetes knowledge (r=0.28,P=0.001).

Discussion
is scoping review of Malaysian literature evaluated 30 cross-sectional studies that measured diabetes knowledge over a 16year period (from 2006 to 2021).Various measurement tools for diabetes knowledge were used across these studies.
e MDKT, which was originally developed by Fitzgerald et al, 18 was most frequently used by Malaysian diabetes researchers in view of acceptable psychometric data in the local setting. 17e MDKT was also noted to be commonly used in two other reviews: a systematic review of diabetes knowledge in Saudi Arabia 19 and a systematic review of dietary knowledge measurement instruments for diabetes. 20ven the wide variation in the contents of the diabetes knowledge measurement tools used among the studies reviewed in this study, it was inappropriate to compare the mean score or proportion between these studies.By limiting the analysis only to the studies that used the MDKT-14, the metaanalysis yielded a more credible pooled mean knowledge score of 6.92 (95% CI=5.45-8.39)and a proportion of a low knowledge level of 47.97% (95% CI=39.13-56.88). is synthesis showed that the mean knowledge score of Malaysian patients with diabetes mellitus is relatively low, with almost half of them having a low diabetes knowledge level (score <7).2][23] Although these systematic reviews used somewhat di erent methodologies, they also found that patients with diabetes mellitus generally had relatively low knowledge scores.Among the Malaysian studies that utilised the MDKT-14, there were associations found between a low knowledge level and certain sociodemographic variables such as Indian ethnicity, older age, lower educational level and lower household income.Notably, these variables are closely related to poverty and social disadvantages and are not amenable to change by healthcare providers.
In the present study, diabetes knowledge was found to be positively associated with health literacy, various self-care activities and glycaemic control (i.e.lower HbA1c levels).
e positive relationship between diabetes knowledge and practice-level outcome is reassuring, as this supports the notion that better diabetes knowledge, probably acting in concert with health literacy and self-e cacy, could lead to better diabetes outcomes. 7,24iabetes knowledge is considered easier to measure among patients with diabetes mellitus than health literacy or self-e cacy, wherein reliable responses require relatively high general literacy levels.
Since diabetes knowledge may be a surrogate marker of health literacy or self-e cacy as well as an immediate outcome of diabetes education, measuring it periodically during long-term care of patients with diabetes mellitus should be considered.Diabetes knowledge among the wider population should be assessed to identify speci c areas of knowledge gaps that deserve closer attention for future educational activities. 25re is currently no attempt to measure diabetes knowledge at the population level in Malaysia within the nationwide Health and Morbidity Surveys.
e Malaysian Diabetes Index in 2021, 26 a nationwide survey of 2539 adults, found that Malaysians had an unsatisfactory level of understanding about diabetes mellitus and were often misinformed about the disease (e.g. one in three Malaysians believed that cutting down sugar is su cient to prevent diabetes mellitus).
is nding shows the urgency of assessing diabetes knowledge, which can provide useful information to inform the e ectiveness of diabetes education on general adults as well as patients with diabetes mellitus.
Notably, having good diabetes knowledge may not automatically translate into appropriate actions at the patient level. 27is common occurrence of knowledge-action gaps points to the need to measure knowledge as well as speci c diabetes mellitus-speci c actions such as appropriate self-care practices and work towards reducing barriers to these practices.Some limitations of this review must be considered.In view of the heterogeneity in the methodologies and objectives across the studies, only a small subset of the studies that used the MDKT reported extractable data for the meta-analysis, reducing the precision of the pooled data (i.e.wider CIs).Further, this review included only cross-sectional studies that measured diabetes knowledge in Malaysia.
e ndings on the associated factors of diabetes knowledge were derived from these cross-sectional studies and thus lack the predictive value that can be obtained only from long-term cohort studies or randomised controlled trials.

Conclusion
is study reviewed fairly extensive research on diabetes knowledge in Malaysia and highlighted a suboptimal knowledge level among adults with and without diabetes mellitus.e results of this review can assist Malaysian diabetes researchers in planning further research regarding diabetes knowledge.

REVIEW
How does this paper make a di erence in general practice?

•
ere is extensive research on diabetes knowledge in Malaysia, most of which is conducted in primary care settings.
• Almost half of adults with diabetes mellitus in Malaysia have poor diabetes knowledge.
• As diabetes knowledge is found to be associated with health literacy, self-care and glycaemic control, periodic assessment and intervention should be considered to improve diabetes knowledge.

Figure 2 .
Figure 2. Meta-analysis of the mean Michigan Diabetes Knowledge Test (MDKT) scores.

Figure 3 .
Figure 3. Meta-analysis of the proportion of a low diabetes knowledge level.

Table 1 .
Studies using a self-developed or modi ed diabetes knowledge scale.
a5Diabetes knowledge measurement tools used Nineteen studies used a named diabetes knowledge scale (Table1), while the rest either used a self-developed questionnaire or adapted a tool from various sources.enames of the diabetes knowledge scales used were as follows: (1) MDKT in 15 studies, with all studies using the 14-item version (MDKT-14) with the exception of the study byAbbasi et al. a1where the MDKT-18 was utilised; the total possible MDKT-14 score ranges from 0 to 14 and is interpreted as follows: low (<7 points), moderate (

Table 2 .
Studies using a self-developed or modi ed diabetes knowledge scale.